Fe2+-dependent enzyme. The enzyme is involved in the biosynthesis of the cyclic pentapeptide antibiotic viomycin. It differs from EC 1.14.11.34, 2-oxoglutarate/L-arginine monooxygenase/decarboxylase (succinate-forming), because it does not form guanidine and (S)-1-pyrroline-5-carboxylate from 3-hydroxy-L-arginine.